The present disclosure relates to a linear movement device.
DE 201 15 647 U1 discloses a linear movement device. According to FIG. 2 in DE 201 15 647 U1, the linear movement device comprises a housing 9 on which a carriage 10; 11 is mounted so as to be movable in a longitudinal direction. The housing is manufactured from aluminum using an extrusion method, wherein the housing has an essentially U-shaped cross-sectional shape. The guide cavity in the interior of the housing is covered by a toothed belt 8 which extends over the entire length of the housing, wherein said toothed belt 8 is attached at both ends to the housing. The corresponding attachment device 3; 4; 5 allows the toothed belt to be placed under a desired tension, with the result that it is just tensioned and defines a toothed belt plane. A plurality of guide rails in the form of circular steel rods are arranged within the guide cavity. A guiding carriage 15 is mounted in a longitudinally movable fashion on these guide rails by means of rotatable running wheels which roll on the guide rails. The guiding carriage is screwed to the carriage. A total of two deflection wheels 13, which deflect the toothed belt out of the toothed belt plane, are held rotatably in the carriage. A rotatable drive wheel 12, which is in drive-transmitting engagement with the toothed belt, is arranged between the two deflection wheels. The drive wheel is provided with a dog clutch, with the result that it can be placed in a rotary drive connection with an electric motor.
The toothed belt drive described above is also referred to as an omega drive since the toothed belt in the carriage is bent in the shape of an Ω. Such drives are preferably used when the carriage is fixedly attached to a superordinate assembly, wherein the housing moves with respect to the carriage. In this context, the omega drive has the advantage that the heavy electric motor is attached to the carriage, with the result that it does not have to be moved along with it. In this arrangement of the linear movement device, depending on the position the housing forms a very long lever arm, with the result that small forces which act on the end of the housing can cause large deflection movements of the housing. Efforts are therefore made to guide the housing on the carriage in a particularly rigid fashion. At the same time, the carriage itself must also be embodied in a very rigid fashion since, owing to the long lever arm of the housing, small deformations at the carriage lead to large deflection movements at the housing. In this context it is to be noted once more that all the external forces are transmitted to the superordinate assembly via the carriage.
The known linear movement device has the disadvantage that the carriage only has a low degree of rigidity. This is due, on the one hand, to the fact that the carriage plate 10 has a comparatively large breakthrough through which the toothed belt is guided and in which the deflection roller 13 is arranged in certain sections. Furthermore, the carriage comprises a separate housing component 11 which is fixedly connected to the carriage plate only at individual attachment points. The composite composed of the carriage plate 10 and housing component 11 is therefore not very rigid and deforms to a great degree under the action of external forces.
The object of the disclosure is to improve the rigidity of the linear movement device specified at the beginning, wherein, in particular, the rigidity of the carriage is to be increased.